Atyrau, Kazakhstan -- Rising demand for a fast-dwindling delicacy, the legendary caviar of the Caspian Sea, has created an unprecedented poaching frenzy for the sturgeon that produces it, law enforcement officials and other sources say.

Poaching has been particularly severe in the pristine Ural River, the last spawning ground of the giant of the family, the coveted beluga. A fisherman can earn between $10,000 and $15,000 for a female beluga's 50 pounds of caviar, or between $200 and $300 a pound, twice the amount the eggs fetched last year. The smaller but more common sevruga and ossetra species bring nearly the same price.

In the past year, the black-gold rush has involved shootouts, disappearances at sea, law-enforcement agencies accusing each other of poaching, and the indictments of four managers of Atyrau Balyk, Atyrau's main cannery, on poaching charges.

As a result, the wildlife protection arm of the United Nations, the Convention on International Trade in Endangered Species, voted this month to force caviar-exporting countries, whose trade is regulated by the agency, to disclose for the first time the scientific justification for continuing exports without further endangering the species. A panel of scientists will later rule whether such exports should continue.

"A system has finally been established that will lift the veil of secrecy off the caviar trade," said Ellen Pikitch, who heads the Pew Institute for Ocean Science at the University of Miami and has been studying Caspian sturgeon for years.

In 2005, the United States listed beluga as a threatened species and banned all imports. In Europe, the pearly black eggs sell for between $2,500 and $4,000 a pound. U.S. consumers are left with wild Caspian sevruga and ossetra, farmed American white sturgeon or farmed French Siberian sturgeon.

The rising prices for caviar in Kazakhstan parallels Atyrau's transformation from a dusty backwater to a booming oil town, where more residents can afford caviar even at today's steep prices. Within the next decade, Kazakhstan is expected to have a ratio of oil revenue to population similar to that of Saudi Arabia.

But the high price of caviar also highlights how deeply overfished the world's last major population of sturgeon has become. The 250 million-year-old species, once plentiful on both U.S. coasts and in Western Europe, has been nearly fished out of the Caspian Sea in the past 20 years.

Before the fall of the Soviet Union in 1991, sea fishing was prohibited to conserve stocks and sturgeon were caught only in nets when swimming upriver to spawn. Now, the soaring profitability of poaching and the widespread realization that sturgeon will soon be gone has prompted a virtual free-for-all to capture the remaining fish, according to scientists and law enforcement officials.

In January, police arrested a manager of the Atyrau Balyk cannery, charging him and three colleagues who had fled to Russia with poaching. The cannery has a monopoly in exporting Kazakhstan's CITES-approved quota, which this year amounts to 1.7 metric tons of beluga caviar and 14 tons of sevruga and ossetra caviar.

"Since the fall of 2004, Atyrau Balyk management has used criminal schemes for tax evasion, money laundering and buying sturgeon illegally caught at sea," said a police statement. Authorities confiscated 4.6 tons of caviar and 78 tons of sturgeon meat.

Later, the KNB, Kazakhstan's successor to the Soviet KGB spy agency, issued a statement noting "the increase of illegal fishing in the Caspian Sea and the highly organized criminal nature of poaching." The agency accused the River Police -- one of 10 agencies responsible for fighting poaching -- of "involvement in illegal fishing."

"Organized provocation!" the head of the River Police, Mereke Izmuratov, told the independent weekly Ak Zhaik. "Those who stand behind this activity want to remove me so they can organize large-scale poaching while the fish are still here."

Local newspapers regularly describe how virtually all of the law-enforcement agencies patrolling the river and sea receive payoffs from poachers or hire poachers themselves.

In addition, machine gun-toting Russian poachers have arrived from nearby Dagestan, near the Volga River, where "pretty much everything has been fished out -- sturgeon and nonsturgeon," said Anatoli, a Kazakh fisherman who asked that his last name not be used.

At least two boats, carrying fishermen and a policeman, have disappeared this year -- likely victims of Russian fishermen, some officials say. "They are armed and they don't hesitate to shoot," said the director of the national fish warden agency, Bakhyt Kametov.

Moreover, many poachers can't distinguish between female and male sturgeon, slicing open the bellies and keeping only the eggs, says a former poacher. When a reporter took a trip near the Ural Delta, he saw as many floating carcasses as the telltale empty plastic bottles that indicate illegal gill nets.

It's been three years since local scientists tallied wild baby sturgeon swimming downriver. At that time, they noted that fewer than 300 adult pairs of the three main species of sturgeon had managed to spawn.

How many survived this year is anyone's guess. But Pew's Pikitch says that because sturgeon reproduce at most every five years, "there will be virtually no more fish left in five years, 10 at the very most."